Hoppers for agricultural implements are frequently completely open at the top. Although open hoppers have been tolerated for years, there are substantial disadvantages. For example, rain, even light rain, can often cause problems with the substance in the hopper, e.g., fertilizer. In the case of a powdered substance, wind may blow more of the substance onto a field than is desired. Also, a covered hopper is safe with respect to people who do not understand the danger of some substances which may be in the hopper.
Hinged doors have sometimes been used on hoppers. Such doors, however, are necessarily large and, consequently, are frequently difficult to operate. It is not uncommon that such doors are removed and simply not used.
A need exists, therefore, for a simple usable door which can readily be opened to expose a substantial portion of the central portion of a hopper to allow for loading of the hopper.